All upgradable epic quality items introduced in Patch 5.4 (items found in Siege of Orgrimmar and Timeless Isle) are now eligible to be upgraded an additional 2 times for a total increase of 16 item levels.

Heirloom weapons awarded by Garrosh Hellscream have been increased by 8 item levels to keep them competitive with the additional 2 upgrade levels given to other items.

Mistweaver Ai on the Timeless Isle next to the Celestial Court now sells a token called Deeds of Valor for 3000 Timeless Coins. When used, Deeds of Valor grants 100 Valor Points to the character, up to the 1000 Valor Point maximum per week.

UI Add-Ons are no longer able to update a number of CVars while the player is in combat. A complete listing of CVars affected by this change can be found in the forum thread titled: 5.4.8 Changes to CVars While In-Combat.

Achievements

Going to Need a Bigger Bag is now an account-wide achievement and items obtained by all characters on the account now contribute credit towards completion. This means the achievement can be completed by obtaining all the required items across multiple characters instead of having a single character obtain all the items needed.